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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 18 |
| 2 | 198 |
| 3 | 1998 |
| 4 | 19998 |
| 5 | 199998 |
| 6 | 1999998 |
| 7 | 19999998 |
| 8 | 199999998 |
| 9 | 1999999998 |
| 10 | 19999999998 |
| 11 | 199999999998 |
| 12 | 1999999999998 |
| 13 | 19999999999998 |
| 14 | 199999999999998 |
| 15 | 1999999999999998 |
| 16 | 19999999999999998 |
| 17 | 199999999999999998 |
| 18 | 1999999999999999998 |
| 19 | 19999999999999999998 |
| 20 | 199999999999999999998 |
[0,18,198,1998,19998,199998,1999998,19999998, 199999998,1999999998,19999999998,199999999998, 1999999999998,19999999999998,199999999999998, 1999999999999998,19999999999999998, 199999999999999998,1999999999999999998, 19999999999999999998,199999999999999999998] |